For more than half a century, an encounter with JD Salinger was akin to
stumbling across the Holy Grail.

The author of The Catcher in The Rye retreated from the public eye in 1953 and lived a hermit-like existence, rarely venturing from his remote New Hampshire home and rebuffing anyone who had the temerity to attempt conversation.

Or so everyone thought. For it turns out that the world's most celebrated literary recluse was not so reclusive after all.

Far from being a curmudgeon who loathed company, Salinger enjoyed coach trips to Nantucket, Niagara Falls and the Grand Canyon, chatting happily to fellow pensioners as he took in the sights.

He even came to Britain several times to visit Whipsnade Zoo, take in an Alan Ayckbourne play and go for dinner at the Savoy.

Previously unpublished letters from Salinger to a British friend reveal fascinating details of his hidden life. The letters cover the most unlikely subjects, from his preferred choice of fast food establishment (Burger King) to his love of British television series (Upstairs Downstairs was a favourite but he didn't think much to Band of Gold).

He had a passion for tennis and an admiration for Tim Henman, saying it would be nice if the British player "knocked 'em all down" and won the 2006 Wimbledon championship. He praised Henman's mother and father for not being "professional tennis parents".

He referred to Ronald Reagan and George Bush in 1988 as "the outgoing dummy and the incoming dummy", and to US politicians as "an odious bunch".

A 1990 trip to Niagara Falls was "oddly pleasing" and his fellow tourists were "more often than not interesting and nice company", although he noted that they were rather overweight.

He described his own appearance in 1986 as "white-haired and creasy".

The cache of 50 typed letters and four handwritten postcards date from 1986-2002 and the recipient was Donald Hartog, who met Salinger in 1937 when they were both 18 and studying German in Vienna. They remained friends for life.

Salinger died in January last year, aged 91. Mr Hartog, a food importer from London, died in 2007 and the letters - signed "Jerry" - passed to his daughter, Frances.

She has donated them to the University of East Anglia, where they will be placed on public display.

Ms Hartog said: "The letters are very touching and they are written very much in the style of his books - casual but using exactly the right words. There is tremendous warmth and affection towards my father and this is so different to how Salinger is often portrayed."

Ms Hartog met Salinger in April 1989 when he came over to attend her father's 70th birthday dinner. She said: "I didn't really want to meet him because I liked his writing and was worried he might live up to his reputation and be rather unpleasant, but he wasn't at all, he was utterly charming."

Salinger's kindness is evident from the letters but he also writes of his disdain for the publishing world and his legal battle to prevent publication of an unauthorised biography. He never recovered from the attention that greeted the publication of The Catcher in The Rye in 1951.

In 1991, he wrote to Mr Hartog of the "ever-present windfall bonanza" of earnings from his old work and said he had spent the past 25 years happily writing without the "distraction" of being published. His wealth meant he did not have to publish anything "unnecessarily or prematurely or even posthumously if it seems a sound idea not to".

A year later, his house in the tiny town of Cornish was devastated by a fire that killed his two greyhounds. He and his wife, Colleen, escaped unharmed and he called it "a larger than life miracle" that firefighters were able to put out the blaze before it reached his work. Fans hope some of it will eventually see the light of day.

Commentary from Prof Christopher Bigsby

When J.D. Salinger died in 2010, obituaries stressed his importance as a writer but also insisted that he had ‘a deep distrust of the world’. He was, we were told, Howard Hughes-like. The New York Times suggested that he was either a crackpot or the American Tolstoy. There is a blurred photograph of him, holding his hand across his face as though to blank out the world.

Now there is a new account, wholly at odds with this portrait. What emerges from these letters is a man who, far from having a distrust of the world, went out into it. He enjoyed coach trips to Nantucket, Niagara Falls and the Grand Canyon and enjoyed, too, chatting to his fellow passengers. This Salinger goes to restaurants, concerts, galleries,the theatre. He describes flying to London in hopes of seeing Chekhov plays or something by Alan Ayckbourn and visiting Covent Garden because his wife Colleen had a liking for My Fair Lady. He goes to the zoo.

At home this Salinger enjoys watching tennis, especially McEnroe and Tim Henman. He likes the Three Tenors, though with a preference for José Carreras. He recommends Burger King hamburgers as being more healthy than others. He is an Upstairs Downstairs addict and works in his garden, driving a tractor and wielding a chain saw. He despises Reagan and Bush and is suspicious of Thatcher. Not so strange, then.

Today, we expect our writers to be public figures. He had no interest in that. He distrusted the media and hated the idea of a biography, but he was scarcely alone in that. He wished simply to write without the distraction of publication. He was not, though, at least as revealed in these letters, a crazed hermit. He liked his privacy but he also went out into the world and took great pleasure in doing so.

Christopher Bigsby is Professor of American Studies at the University of East Anglia